I remixed the back cover of the Heatbed Camera Mount of Nymeia to get ventilation slots inside. That's because the IR Leds get's very hot and therefore a bit ventilation increase their lifetime I guess. The middle ventilation slots are useless but I noticed that after printing :-( Anyway, I leaved them in it.
Print it as it is orientated in CURA. The walls should be printed at last. Then you should have no problems and no need for a Raft or Brim.